“We’ve recently heard from many loyal Apple customers who were disappointed to learn that we had removed our products from the EPEAT rating system,” read a letter from Bob Mansfield, Apple’s senior vice-president of hardware engineering, that was posted on the company’s website. “I recognize that this was a mistake. Starting today, all eligible Apple products are back on EPEAT.”

“It’s important to know that our commitment to protecting the environment has never changed, and today it is as strong as ever. Apple makes the most environmentally responsible products in our industry,” the letter said.

Apple’s withdrawal from the organization came as a surprise to many, especially because it had played a part in coming up with the EPEAT standards.

The move meant that Apple products could no longer be purchased by some organizations, including the city of San Francisco, which mandates EPEAT-approved computers for its staff. Across the U.S. federal government, purchasing standards call for at least 95 percent of computers to be up to EPEAT standards.

It also caused disappointment among many in Apple’s core user base, the very group Mansfield referred to in his letter.

“I am very happy to announce that all of Apple’s previously registered products, and a number of new products, are back on the EPEAT registry,” wrote Robert Frisbee, EPEAT CEO, in a message on the organization’s website. “We look forward to Apple’s strong and creative thoughts on ongoing standards development. The outcome must reward new directions for both design and sustainability, simultaneously supporting the environment and the market for all manufacturers’ elegant and high-performance products.”

Apple’s return to EPEAT was marked with the awarding of a “gold” rating to the company’s 15-inch MacBook Pro with Retina display. That represents EPEAT’s highest rating.

“I think this is a great example of them listening to customers who don’t want [their computers] designed against the environment,” said Casey Harrell, a spokesman for Greenpeace. “But the devil may be in the details. At least the first shipments of the new MacBook Pros have the batteries glued to the casing, and that makes it very difficult to take them out and recycle.”

After Apple’s withdrawal from the group, there had been speculation that the company’s use of glue to hold in batteries and displays in some new products was causing a problem with environmental certification. Glue would make it more difficult to recycle the products.

An EPEAT spokeswoman declined to address the specifics of Apple’s design but explained the basic rating is awarded for passing 23 mandatory requirements. Passing 50 per cent of optional requirements results in a silver rating, and the gold standard is awarded to products that meet at least 75 percent of optional EPEAT criteria. That leaves some room for products to get top marks even if they fail in some areas.

With Apple [Nasdaq: AAPL] back in the group, it will now be able to participate in discussions currently taking place toward a revision of the standard for computers and monitors.

“They will be updated and obviously all the stakeholders want to see innovation and forward-looking design incorporated,” said Sarah O’Brien, director of outreach and communications for EPEAT.